from django.http import HttpResponse, Http404, HttpResponseRedirect
from django.template import loader
from django.shortcuts import render, get_object_or_404
from django.urls import reverse
from django.views import generic
from django.utils import timezone

from .models import Question, Choice

"""
def index(request):
  latest_question_list = Question.objects.order_by('-pub_date')[:5]
  # print(latest_question_list)
  # output = ', '.join([q.question_text for q in latest_question_list])
  # return HttpResponse(output)

  # template = loader.get_template('polls/index.html')
  context = {
    'latest_question_list': latest_question_list
  }
  # return HttpResponse(template.render(context, request))

  return render(request, 'polls/index.html', context)



def detail(request, question_id):
  # try:
  #   question = Question.objects.get(pk=question_id)
  # except Question.DoesNotExist:
  #   raise Http404('Question does not exist.')

  question = get_object_or_404(Question, pk=question_id)
  #  get_list_or_404(): get() 函数被换成了 filter() 函数

  return render(request, 'polls/detail.html', {'question': question})


def results(request, question_id):
  question = get_object_or_404(Question, pk=question_id)

  return render(request, 'polls/results.html', {'question': question})
"""

class IndexView(generic.ListView):
  template_name = 'polls/index.html'
  context_object_name = 'latest_question_list'

  def get_queryset(self):
    # return Question.objects.order_by('-pub_date')[:5]
    return Question.objects.filter(
      pub_date__lte=timezone.now()
    ).order_by('-pub_date')[:5]

class DetailView(generic.DetailView):
  model = Question
  # template_name = 'polls/detail.html'
  def get_queryset(self):
    return Question.objects.filter(
      pub_date__lte=timezone.now()
    )

class ResultsView(generic.DetailView):
  model = Question
  template_name = 'polls/results.html'


def vote(request, question_id):

  question = get_object_or_404(Question, pk=question_id)
  try:
    selected_choice = question.choice_set.get(pk=request.POST['choice'])
  except (KeyError, Choice.DoesNotExist):
    return render(request, 'polls/detail.html', {
      'question': question,
      'error_message': 'You didn`t select a choice.'
    })
  else:
    selected_choice.votes += 1
    selected_choice.save()

    return HttpResponseRedirect(reverse('polls:results', args=(question.id,)))


